This invention relates to a method of a power switching device for polarity-independent reduction of feedback from a complex consumer or consumers periodically connected with an A.C. line. The invention relates, more particularly, to such a method and device provided with interruption of the connection of the consumer or consumers to the line occurring in each half wave of the A.C. line voltage.
It has been proposed, as disclosed in a patent application of Hans-Dieter Grudelbach, Ser. No. 773,279 filed on even date and based on Swiss Patent Application No. 11447/76 filed Sept. 9, 1976, to regulate the electrical power supplied to a consumer (utilization device) in an A.C. network by setting the corresponding current flow angle in such manner that the consumer is disconnected from the A.C. line during each half wave at a phase angle of the A.C. line voltage which corresponds to the desired current flow angle. The consumer consequently is connected to the line at least, approximately, at the zero cross-over point of the A.C. line voltage. In this arrangement, it is the energy stored up electrically or magnetically at the moment of disconnection that dies out and dissipated in the consumer. It is assumed in this connection that a voltage surge can occur. Since the consumer also usually includes inductive and capacitive components, temporary changes in the direction of flow of the current are unavoidable in the consumer. Moreover, it is necessary to maintain similarity between the electrical state in the consumer and in the line, if the consumer is to receive additional current, or allowance must be made for the fact that additional peak loads will be produced.